HP-UX Reference (11i v2 07/12) - 1M System Administration Commands A-M (vol 3)

m
mount_nfs(1M) mount_nfs(1M)
Options (umount)
umount recognizes the following options:
-a Attempt to unmount all file systems described in
/etc/mnttab . All optional fields
in
/etc/mnttab must be included and supported. If
-F nfs option is specified, all
NFS file systems in
/etc/mnttab are unmounted. File systems are not necessarily
unmounted in the order listed in /etc/mnttab .
-f Forcibly
unmount a file system. Without this option, umount does not allow a file
system to be unmounted if a file on the file system is busy. Using this option can
cause data loss for open files; programs which access files after the file system has
been unmounted will get an error ([EIO]).
-F nfs Specify the NFS file system type (see fstyp(1M)).
-h host Unmount only those file systems listed in
/etc/mnttab that are remote-mounted
from host.
-v Verbose mode. Write a message to standard output indicating which file system is
being unmounted.
-V Echo the completed command line, but performs no other action. The command line
is generated by incorporating the user-specified options and other information derived
from /etc/fstab . This option allows the user to verify the command line.
NFS File Systems
Background vs. Foreground
File systems mounted with the bg option indicate that mount is to retry in the background if the
server’s mount daemon (mountd) does not respond.
mount retries the request up to the count
specified in the
retry=n option. Once the file system is mounted, each NFS request made in the
kernel waits timeo=n tenths of a second for a response. If no response arrives, the time-out is mul-
tiplied by 2 and the request is retransmitted. When the number of retransmissions has reached the
number specified in the retrans=n option, a file system mounted with the soft
option returns an
error on the request; one mounted with the
hard option prints a warning message and continues to
retry the request.
Hard vs. Soft
File systems that are mounted read-write or that contain executable files should always be mounted
with the hard option. Applications using soft mounted file systems may incur unexpected I/O
errors.
To improve NFS read performance, files and file attributes are cached. File modification times get
updated whenever a write occurs. However, file access times may be temporarily out-of-date until the
cache gets refreshed. The attribute cache retains file attributes on the client. Attributes for a file are
assigned a time to be flushed. If the file is modified before the flush time, then the flush time is
extended by the time since the last modification (under the assumption that files that changed
recently are likely to change soon). There is a minimum and maximum flush time extension for regu-
lar files and for directories. Setting actimeo=n sets flush time to n seconds for both regular files
and directories.
EXAMPLES
To mount an NFS file system:
mount serv:/usr/src /usr/src
To mount an NFS file system readonly with no suid privileges:
mount -r -o nosuid serv:/usr/src /usr/src
To mount an NFS file system over Version 3:
mount -o vers=3 serv:/usr/src /usr/src
To unmount all file systems imported from a given host, enter the following command as root:
umount -h mysystem.home.work.com -a
The hostname must match what is in /etc/mnttab exactly (as shown by the bdf command). For exam-
ple, if bdf shows:
HP-UX 11i Version 2: December 2007 Update − 3 − Hewlett-Packard Company 603